Atherectomy and thrombectomy are procedures for removing plaques and thrombus from the vasculature. Plaques are more robust and anchored to the vessel walls relative to thrombus, which has a softer consistency and is more easily removed from the vessel.
In some examples, atherectomy catheters remove plaques from vessel walls through mechanical engagement and abrasion of plaques. The mechanical removal of plaques generates loose particulate matter within the vessel wall that increases the risk of emboli within the blood stream.
Similarly, in some examples, thrombectomy procedures remove thrombus from vessel walls through mechanical systems that mechanically engage and remove thrombus, for instance by cutting of the thrombus with one or more features at the end of a catheter. In still other examples, catheters include hydrodynamic features that generate streams of solution, such as saline, that engage with thrombus and hydrodynamically remove thrombus from the vessel walls. In yet other examples, solutions such as lytic medicants are delivered to thrombus within the vasculature, and the medicants breakdown the thrombus.
In some examples, atherectomy catheters include cutters coupled with a drive shaft to mechanically abrade plaques. The drive shaft extends through an aspiration lumen. Effluent (infusion fluid including entrained particulate) flows around the drive shaft during use of the catheter including rotation of the drive shaft to accordingly rotate the cutters. In still other examples, guide wires are delivered through the drive shaft to a distal portion of the catheter and into the vasculature. The catheter is translated through the vasculature according to the track of the guide wire. Because the drive shaft is within the aspiration lumen the guide wire is also positioned within the aspiration lumen with the effluent during operation.
Infusion fluid is delivered through an infusion lumen extending through the catheter body. The aspiration lumen also extends through the catheter body and is adjacent to the infusion lumen. The infusion fluid is delivered through the infusion lumen at an elevated pressure, for instance from 50 to 500 psi. The elevated pressure ensures the infusion fluid is delivered under pressure to the catheter distal portion for entrainment of particulate for eventual aspiration through the aspiration lumen and/or to provide for balanced inflows and outflows, as well as lubrication of moving components.